In the existing reciprocating piston type internal combustion engine, a crank-connecting rod is used to achieve reciprocating movement of the piston. In order to overcome shortcomings of the crank-connecting rod mechanism, such as the reciprocating inertial force, several kinds of engine have been developed. One of them is a reciprocating piston type internal combusion engine with a crank circular slide block, in which the crank-connecting rod is replaced by a circular slide block(s). "An internal combustion engine without crank-connecting rod" developed by the Japanese Institute of Technology disclosed in "The internal combustion Engine", No 8, 1981, wherein the cylinders are arranged as a cross and the accident frequently occurs because the lubricating oil tends to enter the top portion of the piston. In addition, it was proposed that the structure of the sun gear system was arranged to the crank circular slide block mechanism in order to solve the equilibrium problem. However, it is difficult for that structure to be widely used because of its complicated structure. In an internal combusion engine with a crank circular slide block filed by the applicant, disclosed in CN85100358A issued by the Chinese Patent Office, a single circular slide block cooperating with a pair of inner gear transmiting pair is used. Its structure is quite simple, its weight is lower, but its dynamic equilibrium performance is still not perfect.
In veiw of these reasons, the purpose of present invention is to provide a reciprocating piston type internal combusion engine having a crank-dual circular slide block mechanism, which has very good eqilibrium performance and reliability and can save fuel and is simple in structure, smaller in volume and lower in weight.